An outspoken critic of the government’s electronic surveillance programs, U.S. Sen. Mark Udall of Colorado said Sunday he was not convinced that a program to collect huge amounts of information about Americans’ phone calls had led to the foiling of any terror plots. He also called for a renewed debate over the Patriot Act, which authorizes much of the data collection.

In making the assertion, Udall, a Democrat and a member of the Senate Intelligence Committee, appeared to be distinguishing the results of that program — which uses metadata associated with phone calls, including numbers called and the duration of conversations — from those of the newly revealed PRISM program, which analyzes data collected from foreigners who use Internet services such as Facebook and Skype. Several officials have said PRISM has been effective.

“It’s unclear to me that we’ve developed any intelligence through the metadata program that has led to the disruption of plots that we couldn’t have developed through other data and other intelligence,” Udall said on the CNN program “State of the Union.”

Udall, who for years has criticized electronic data collection by the government as too sweeping, called for a reopening of debate over the Patriot Act and a “fulsome debate” on the limits of government intrusion as it seeks to deter terrorist threats.

Government officials also had sharp words for the person who leaked the documents describing classified surveillance programs to The Guardian and The Washington Post. In an interview with NBC News, James R. Clapper, the director of national intelligence, warned that the revelations could create serious risks to national security.

“For me, it is literally — not figuratively — literally gut-wrenching to see this happen, because of the huge, grave damage it does to our intelligence capabilities,” he said.

Rep. Mike Rogers, chairman of the House Intelligence Committee, spoke with barely disguised anger about Glenn Greenwald, whose articles in The Guardian newspaper last week described the surveillance programs.

Greenwald “says that he’s got it all and now is an expert on the program,” Rogers said on the ABC program “This Week.” “He doesn’t have a clue how this thing works. Neither did the person who released just enough information to literally be dangerous.”

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